Muffle roasting-furnace.



No. 731,114. PATENTED JUNE 16, 1903. F. MEYER.

MUFPLE ROASTING FURNACE APPLICATION FILED APR. 21, 1903.

N0 MODEL. 3 SHEETS-SHEET 1.

PATENTED JUNE 16, 1903.

I. MEYER. MUFPLE ROASTING FURNACE. APPLICATION FILED APR. 21, 1903. no MODEL. a SHEETS-SHEET 2.

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UNITED STATES Patented J'unel6, 1903.

FRANZ MEYER, OF NEW YORK, N. Y.

MUFFLE ROASTING-FURNACE.

SIPEOIFICATION forming part of Letters Patent No."731,114, dated June 6, 1903- .Applieation filedApril 21, 1903- To all whom it may concern:

Be it known that I, FRANZ MEYER, a subject of the Emperor of Germany, residing in the city, county, and State of New York, have invented certain new and useful Improvements in Muffle Roasting-Furnaces; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to certain new and useful improvements in muffle roasting-furnaces wherein the ore to be roasted or desulfurized is caused to travel by the action of mechanical stirrers from the feed-opening to the discharge-opening through a series of superposed hearths, discharging from one to the other.

The object of my invention is to provide -a plurality or series of roasting chambers or furnaces which are heated from a common source, and to that end comprises a series of chambers, each made up of a number ofsuperposed hearths, over which the ore is caused to pass successively, a source of heat common to the series, and heat-conducting flues extending below the lower hearths of the series and returning above the roofs of said hearths whereby the heating-gases are caused to travel in such relation to the individual members of the series of chambers that all of the chambers are equably heated and the several hearths of each chamber are heated so that the temperatures thereof shall vary successively from the lower hearth, where it is hottest, to the upper hearth, which receives the ore. As the heating gases are thus caused to travel a long and devious path, the heat contained in them is utilized to its greatest extent in roasting the ore and considerable economyin fuel is maintained. 7

My invention also consists in certain details of construction of the revolving stirrers and their adjuncts, all of which is more particularly hereinafter setforth.

In the accompanying drawings, Figure l is a front elevation, partly in section, of a 'series of chambers or roasting-furnaces arranged according to myinvention. Fig. 2 is a longitudinal section on line 2 2, Fig. 1. Fig. 3 is a horizontal section on line 3 3, Fig. 1. Figs. 4 and 5 are detail views of the stir- Serialll'o; 153,684. (No model.)

naces to the separate discharge-outlets 2 It is to be observed that the invention is not confined to any particular number or arrangement of'furnaces c'ombinedas a unit, as the number and arrangement must be determined by the economic conditions of the particular plant. Neither is the invention concerned in the structural detailssucl1 as the character of the walls, whether straight or curved, or the manner of anchoring the furnace against expansion by heatas all such matters may be left to the sound judgment and discretion of the designer.

Each hearth is provided with rotary stirrers 3, mounted upon a stirrer column passing centrally through the vertical series of hearths comprising the individual furnaces, which columns are rotated by suitable gearing 3 driven from power-shafts 3 located in galleries beneath the furnaces. The stirrerblades of course are arranged to distribute the ore evenly over the hearths and force it gradually toward the openings connecting the respective hearths.

In order to economize in the amount of fuel required to heat the'several furnaces and at the same time to secure the most effective and efficient roasting operation, the several roasting-furnaces are heated from a common source, consisting of one or more heatingfurnaces located at the lower forward end of the series. In the particular embodiment of my invention illustrated two heating-furnaces 1O 10 are shown 1ocated, respectively, below and in front of the two rows of roasting-furnaces, and a third heating-furnace 10 is located midway-between furnaces 10 10. Heating-furnaces 1O 1O connect directly with longitudinal lines 11, running transversely beneath the lowermost hearths of each furnace-row, which connect by vertical flues 11 with return-flues 13, which pass over the roofs of the lower series of hearths and between the latter and the series of hearths immediately above. The products of combustion from furnace 10, located between the furnace-rows, are divided and pass by way of flues 12 12 to the rear of the respective rows, where they discharge into the vertical flues 11 in common with the products from the respective furnaces 10 10. From the flues 13 the products of combustion-pass by way of connectingfiues 14: 14: to stacks 15, located on opposite sides of the furnace structure. The stirrer-columns in their passage through the heating-flues are protected from the hot gases by circular walls of masonry or tiling 11' and 13, located in the respective fiues 11 and 13 and built into the adjacent masonry. The stirrers 3 comprise hollow radial arms having dependent teeth or blades and tapered ends 3 of angular cross-section, whichare fitted into corresponding angular orifices 3 of the stirrer-columns and are held rigidly in position on the columns by means of through bolts 3 passing through the hollow arms and retained by wedges or cotters 3 passing through suitable slots in the ends of the bolts. The stirrer-columns are hollow and connect with the several hollow stirrer-arms in order to permit a circulation of air to cool the parts.

The operation is substantially as follows: The properly-prepared ore in hoppers 4 4; is fed in suitable quantities to the upper hearths of the several furnaces, where it is subjected to an initial roasting and distributed over the surface of the hearths by the stirrer-blades. From thence it passes to the subjacent hearths of the series, where it is subjected to successively-increasing temperatures until it arrives at the lowermost hearths, where the final roasting is efiected. At these points the ore is subjected to the influence of the hot products of combustion passing from furnaces 10 and 10' along the flues 11 and 12 underneath the hearths and thence along the longitudinal flues 13, which ooversubstantially the whole of the roofs of the lower hearths and are connected by flues 13 It will thus be seen that the mean heating effect of the upper and lower flues upon the lower hearths of each furnace is practically uniform and that the several hearths arranged above each of the lower hearths will be supplied with the successively-diminishin g degrees of heat necessary to the proper treatment of the ore. As each furnace is separate and independent of the rest and is provided with its own individual stirring apparatus, any furnace may be isolated at will, and it is only necessary that the furnace affected be shut down in case of a breakdown.

It will of course be understood that any suitable solid, liquid, OPQELSGOUS fuel may be employed for the heating-furnace.

Having thus described my invention, what I claim is 1. A muffie roasting-furnace, consisting of a plurality of vertical chambers, each made up of a series of superposed hearths discharging from one to the other and having rotary stirrers mounted upon a vertical shaft, and a heating-furnace common to the series; substantially as described.

2. A muffle roasting-furnace, consisting of a plurality of vertical chambers, each made up of a series of superposed hearthsdischarging from one to the other and having rotary stirrers mounted upon a vertical shaft, and a heating-furnace common to the series, the fines of said heating-furnace extending below the lower hearths of the series and above the roofs of said hearths; substantially as described.

3. A muffie roasting-furnace consisting of two rows of chambers, each chamber made up of a series of hearths discharging from one to the other and each being provided with hearth-stirrers, a heating-furnace common to each row, and an intermediate heating-furnace common to both rows; substantially as described.

4. A stirrer-column provided with stirrerblades, the inner ends of said stirrer-blades being of angular cross section and fitting within corresponding angular orifices of the stirrer-columns; substantially as described.

5. A stirrer-column provided with stirrerblades, the inner ends of said stirrer-blades being of angular cross-section and fitting within corresponding angular orifices of the stirrer columns, in combination with a through-bolt passing through both stirrer blades for securing them jointly to the columns; substantially as described.

In testimony whereof I afiix my signature in presence of two witnesses.

FRANZ MEYER. WVitnesses:

GUSTAV HARTMANN, H. SCHWEINEBERG. 

